Objective: Recent studies in troops deployed to Iraq and Afghanistan have shown that combat exposure and exposure to deployment-related stressors increase the risk for the development of mental health symptoms. The aim of this study is to assess the prevalence of mental health symptoms in a cohort of Dutch military personnel prior to and at multiple time-points after deployment.

Methods: Military personnel (n=994) completed various questionnaires at 5 time-points; starting prior to deployment and following the same cohort at 1 and 6months and 1 and 2years after their return from Afghanistan.

Results: The prevalence of symptoms of fatigue, PTSD, hostility, depression and anxiety was found to significantly increase after deployment compared with pre-deployment rates. As opposed to depressive symptoms and fatigue, the prevalence ofPTSD was found to decrease after the 6-month assessment. The prevalence of sleeping problems and hostility remained relatively stable.

Conclusions: The prevalence of mental health symptoms in military personnel increases after deployment, however, symptoms progression over time appears to be specific for various mental health symptoms. Comprehensive screening and monitoring for a wide range of mental health symptoms at multiple time-points after deployment is essential for early detection and to provide opportunities for intervention.